Silicon Nitride Substrate Composition for Thermal and Strength Control

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Solution Overview

Problem

Existing methods fail to effectively control the thermal conductivity and flexural strength of silicon nitride substrates, which are crucial for high-output power devices, due to the lack of a systematic approach to adjust the residual magnesium content during manufacturing.

Innovation Solution

A method involving the preparation of a slurry with silicon nitride powder, ceramic additives containing magnesium oxide, and a solvent, followed by molding, degreasing, and sintering processes, where the residual magnesium content is adjusted through control of sintering temperature, sheet size, and atomic ratio of magnesium to yttrium in the ceramic additive, to inversely proportionally affect thermal conductivity and proportionally affect flexural strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the residual magnesium content is increased to improve flexural strength, then the thermal conductivity decreases

Engineering Contradiction:

Improveflexural strengthVSAvoidthermal conductivity

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The patent applies parameter changes by systematically adjusting the sintering temperature, sheet size, and atomic ratio of magnesium to yttrium in the ceramic additive. These parameter modifications enable precise control over the residual magnesium content, allowing optimization of both flexural strength and thermal conductivity based on specific application requirements

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the sintering temperature is increased to reduce residual magnesium content, then the thermal conductivity improves but the manufacturing complexity increases

Engineering Contradiction:

Improvethermal conductivityVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent employs parameter changes by establishing specific sintering temperature ranges (1850-2000°C) and corresponding sheet size specifications. These defined parameter ranges provide a systematic approach to controlling residual magnesium content while maintaining manageable manufacturing complexity through standardized process parameters

Inventive Principle:

Principle #35Parameter changes

3Reliability

If the sheet size is reduced to decrease residual magnesium content, then the thermal conductivity improves but the manufacturing precision requirements increase

Engineering Contradiction:

Improvethermal conductivityVSAvoidsheet size control precision

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by defining specific sheet size ranges (50-200 mm in both length and width directions) that correspond to desired residual magnesium content levels. These standardized size specifications enable control of thermal conductivity while maintaining feasible manufacturing precision through established dimensional tolerances

Inventive Principle:

Principle #35Parameter changes

4Reliability

If the atomic ratio of magnesium to yttrium is adjusted to control residual magnesium content, then the flexural strength and thermal conductivity are optimized but the ease of manufacture decreases

Engineering Contradiction:

Improvethermal conductivityVSAvoidease of manufacture

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by establishing specific atomic ratio ranges of magnesium to yttrium (1:3 to 1:1) in the ceramic additive. These defined ratio specifications enable simultaneous optimization of flexural strength and thermal conductivity, though they do require precise compositional control during material preparation

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs composite materials by using a ceramic additive containing both magnesium oxide and yttrium oxide in specific atomic ratios. This composite approach allows controlled release of magnesium during sintering to achieve desired residual content, while yttrium provides structural stability, thereby optimizing both mechanical and thermal properties

Inventive Principle:

Principle #40Composite materials

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This method allows for precise adjustment of thermal conductivity and flexural strength of silicon nitride substrates, enabling them to meet specific performance requirements by controlling the residual magnesium content, thereby enhancing their suitability for high-output power devices.

Implementation Method 1

Due to high electrical insulation and high thermal conductivity, ceramic materials are suitable for use as a heat transfer medium to rapidly dissipate heat generated by a device

Methodology Applied

Scientific EffectThermal conductivity: Conduction (thermal)

Implementation Method 2

subjecting the stack structure to a sintering process

Methodology Applied

Scientific EffectSintering: Sintering

Data Source

PatentUS20250382233A1Method for controlling thermal conductivity and flexural strength of silicon nitride substrate

Publication Date: 2025.12.18 OCI CO LTD(KR)

AI summary

The present invention relates to a method for controlling physical properties of a silicon nitride substrate, and more specifically, the method comprises the steps of: producing a silicon nitride substrate; and adjusting a residual magnesium content in the silicon nitride substrate. The thermal conductivity of the silicon nitride substrate is inversely proportional to the residual magnesium content in the silicon nitride substrate, and the flexural strength of the silicon nitride substrate is proportional to the residual magnesium content in the silicon nitride substrate.